The Skeletal System - Coral Springs Charter School

1 Essentials of Human Anatomy & Physiology Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Seventh Edition Elaine N. Marieb Chapter 5 The Skeletal System The Skeletal System Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Parts of the Skeletal System Bones (skeleton) Joints Cartilages Ligaments (bone to bone)(tendon=bone to muscle) Divided into two divisions Axial skeleton Appendicular skeleton limbs and girdle Functions of Bones Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Support of the body Protection of soft organs Movement due to attached Skeletal muscles Storage of minerals and fats Blood cell formation Bones of the Human Body Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The skeleton has 206 bones Two basic types of bone tissue Compact bone Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Figure Classification of Bones Slide Copyright 2003 Pearson Education, Inc.

2 Publishing as Benjamin Cummings Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Examples: Femur, humerus Classification of Bones Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Short bones Generally cube-shape Contain mostly spongy bone Examples: Carpals, tarsals Classification of Bones Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum Classification of Bones Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Irregular bones Irregular shape Do not fit into other bone classification categories Example: Vertebrae and hip Classification of Bones on the Basis of Shape Slide Copyright 2003 Pearson Education, Inc.

3 Publishing as Benjamin Cummings Figure Gross Anatomy of a Long Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone Figure Structures of a Long Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey s fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients Figure Structures of a Long Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Articular cartilage Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces Figure Structures of a Long Bone Slide Copyright 2003 Pearson Education, Inc.

4 Publishing as Benjamin Cummings Medullary cavity Cavity of the shaft Contains yellow marrow (mostly fat) in adults Contains red marrow (for blood cell formation) in infants Figure Bone Markings Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Three broad categories of bone markings Projections for muscle attachment Surfaces that form joints Depressions or cavities indentations Bone Markings Table (1 of 2) Bone Markings Table (2 of 2) Microscopy Anatomy of Bone Bone Histology Microscopic Anatomy of Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Osteon (Haversian System ) A unit of bone Central (Haversian) canal Opening in the center of an osteon Carries blood vessels and nerves Perforating (Volkman s) canal Canal perpendicular to the central canal Carries blood vessels and nerves Microscopic Anatomy of Bone Slide Copyright 2003 Pearson Education, Inc.

5 Publishing as Benjamin Cummings Figure Microscopic Anatomy of Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal Sites of lacunae Figure Microscopic Anatomy of Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Canaliculi Tiny canals Radiate from the central canal to lacunae Form a transport System Figure Changes in the Human Skeleton Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints Bone Growth Slide Copyright 2003 Pearson Education, Inc.

6 Publishing as Benjamin Cummings Epiphyseal plates allow for growth of long bone during childhood New cartilage is continuously formed Older cartilage becomes ossified Cartilage is broken down Bone replaces cartilage Bone Growth Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bones are remodeled and lengthened until growth stops Bones change shape somewhat Bones grow in width Long Bone Formation and Growth Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Types of Bone Cells Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Osteocytes Mature bone cells Osteoblasts Bone-forming cells Osteoclasts Bone-destroying cells Break down bone matrix for remodeling and release of calcium Bone remodeling is a process by both osteoblasts and osteoclasts Bone Fractures Slide Copyright 2003 Pearson Education, Inc.

7 Publishing as Benjamin Cummings A break in a bone Types of bone fractures Closed (simple) fracture break that does not penetrate the skin Open (compound) fracture broken bone penetrates through the skin Bone fractures are treated by reduction and immobilization Realignment of the bone Common Types of Fractures Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Table Fractures are also categorized based on the shape of the break. There are eight main shapes or kinds of bone fractures. Transverse fractures: go more or less straight across the bone. Oblique fractures: are diagonal breaks across the bone. Spiral fractures: happen when one or both halves of the bone are twisted. Comminuated fractures: break the bone into more than two pieces. Avulsion fractures: mean pieces of the bone have been pulled apart. Impacted fractures: are the opposite of avulsion fractures.

8 These happen when a piece of bone is pushed down into another piece of bone. Fissure fractures: are cracks in the bone. Greenstick fractures: happen when the bone bends and breaks partially, but not completely. Transverse fractures: go more or less straight across the bone. Oblique fractures: are diagonal breaks across the bone. Spiral fractures: happen when one or both halves of the bone are twisted. Comminuated fractures: break the bone into more than two pieces. Avulsion fractures: mean pieces of the bone have been pulled apart. Impacted fractures: are the opposite of avulsion fractures. These happen when a piece of bone is pushed down into another piece of bone. Fissure fractures: are cracks in the bone. Greenstick fractures: happen when the bone bends and breaks partially, but not completely. Repair of Bone Fractures Slide Copyright 2003 Pearson Education, Inc.

9 Publishing as Benjamin Cummings Hematoma (blood-filled swelling) is formed Break is splinted by fibrocartilage to form a callus Fibrocartilage callus is replaced by a bony callus Bony callus is remodeled to form a permanent patch Stages in the Healing of a Bone Fracture Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure The Axial Skeleton Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Forms the longitudinal part of the body Divided into three parts Skull Vertebral column Bony thorax The Axial Skeleton Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure The Skull Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two sets of bones Cranium Facial bones Bones are joined by sutures Only the mandible is attached by a freely movable joint The Skull Slide Copyright 2003 Pearson Education, Inc.

10 Publishing as Benjamin Cummings Figure Bones of the Skull Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Human Skull, Superior View Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Human Skull, Inferior View Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Paranasal Sinuses Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hollow portions of bones surrounding the nasal cavity Figure Paranasal Sinuses Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Functions of paranasal sinuses Lighten the skull Give resonance and amplification to voice Figure The Hyoid Bone Slide Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The only bone that does not articulate with another bone Serves as a moveable base for the tongue Figure The Fetal Skull Slide Copyright 2003 Pearson Education, Inc.